This study aims to discover the stress-state dependence of the dynamic strain aging (DSA) effect on the deformation and fracture behavior of high-strength dual-phase (DP) steel at different deformation temperatures (25–400°C) and reveal the damage mechanisms under these various configurations. To achieve different stress states, predesigned specimens with different geometric features were used. Scanning electron microscopy was applied to analyze the fracture modes (e.g., dimple or shear mode) and underlying damage mechanism of the investigated material. DSA is present in this DP steel, showing the Portevin-Le Chatelier (PLC) effect with serrated flow behavior, thermal hardening, and blue brittleness phenomena. Results show that the stress state contributes distinctly to the DSA effect in terms of the magnitude of thermal hardening and the pattern of blue brittleness. Either low stress triaxiality or Lode angle parameter promotes DSA-induced blue brittleness. Accordingly, the damage mechanisms also show dependence on the stress states in conjunction with the DSA effect.

本研究旨在发现动态应变时效（DSA）效应对高强度双相（DP）钢在不同变形温度（25–400°C）下的变形和断裂行为的应力状态依赖性，并揭示出这些不同配置下的损坏机制。为了获得不同的应力状态，使用了具有不同几何特征的预先设计的标本。应用扫描电子显微镜分析被研究材料的断裂模式（例如，凹痕或剪切模式）和潜在的损伤机理。DSA存在于这种DP钢中，显示出Portevin-Le Chatelier（PLC）效应，具有锯齿状的流动行为，热硬化和蓝色脆性现象。结果表明，就热硬化的幅度和蓝色脆性的模式而言，应力状态对DSA效应有明显的影响。低应力三轴性或洛德角参数都会促进DSA引起的蓝色脆性。因此，损伤机制还显示出与应力状态的相关性以及DSA效应。